Elevated temperature liquid heating systems



Unite States Patent 3,029,795 ELEVATED TEMPERATURE LIQUID HEATING SYSTEMS Wayne W. Binger and David G. Vandenburgh, New Kensington, Pa., assignors to Aluminum Company of America, Pittsburgh, Pa., a corporation of Pennsylvania Filed Nov. 25, 1958, Ser. No. 776,317 4 Claims. (Cl. 122-14) This invention relates in general to closed liquid systems operating at elevated temperatures and is more particularly addressed to closed hot water systems and modified construction of the conventional storage vessels or tanks employed in such systems.

The presence of loose insoluble deposits or residues in the liquid media within closed liquid systems operating at elevated temperatures has been observed to be a source of erratic and objectionable operation of such systems, particularly when the insoluble deposits are permitted to collect and accumulate on the liquid side of under-fired or exteriorly heated bottom end closure crown sheets of the storage tanks, in which case such accumulations have been found to develop rumbling noises within the systems. Copending application, Serial No. 748,666, filed July 15, 1958, in the names of David G. Vandenburgh, Wayne W. Binger, and Basil M. Ponchel, is addressed to closed elevated temperature liquid heating systems developed to overcome the aforesaid objectionable and noisy operating conditions.

The loose insoluble deposits in elevated temperature closed liquid systems, and particularly in hot water systems which are contemplated herein, are attributable to many sources, such as precipitation products, organic and inorganic salts and compounds, entrained solids in the liquid supply, and products of corrosion generated from the materials of the tanks, galvanic anodes and the piping employed in such systems.

It is a primary object of the instant invention to prevent the accumulation of substantial quantities of insoluble residues on the liquid side of under-fired or heated bottom end enclosure crown sheets of storage tanks in elevated temperature closed liquid heating systems.

Another object of the invention is to provide storage tank structures which incorporate means for arresting and collecting substantial quantities of the insoluble deposits, normally present in the liquid contents of such storage tanks, at some level above and out of contact with the bottom end under-fired crown sheets of the tanks.

Other objects and advantages will be understood to those skilled in the art to which this invention appertains and particularly after consideration of the following description and drawings, in which:

FIG. 1 illustrates a conventional lateral flue elevated temperature liquid heating system and storage tank, in

sectional elevation, incorporating one embodiment of the invention;

FIG. 2 illustrates a transverse sectional view taken on the plane 22 of FIG. 1;

FIG. 3 illustrates a conventional central flue elevated temperature liquid heating system and storage tank, in sectional elevation, incorporating a second embodiment of the invention; and

FIG. 4 illustrates a transverse sectional view taken on the plane 44 of FIG. 3.

Two conventional hot water heating systems incorporating holding or storage tanks have been selected for purposes of illustrating the invention, which basically com prises the provision of means within each of the tanks, preferably located slightly above the bottom end closures thereof, for arresting and collecting the insoluble residues or deposits, normally present in liquid media, and particularly in most water sources, to thereby prevent any substantial accumulation of the deposits on the liquid side of the under-fired bottom end crown sheets of the storage tanks.

Referring now to FIGS. 1 and 2, a conventional hot water storage tank is illustrated as comprising a cylindrical metal body section 10, a top end closure plate or crown sheet 12 and a bottom end closure plate or crown sheet 14. The elements 10, 12 and 14 are preferably constructed from a metal or metal alloy and may be treated on the interior surface of the tank to improve its corrosion resistance against water or other liquid media stored therein.

The storage tank of the system of FIGS. 1 and 2 is illustrated as a conventional lateral flue type of tank, the lateral flue 16 being employed for conducting the hot gases and products of combustion generated by a multi-port ring or annulus burner 22, disposed below the bottom crown sheet 14, upwardly along the exterior surface of the tank body and eventually discharging the same through a stack (not shown) to atmosphere. The burner 22 is usually provided with a plurality of fuel jets directed against an appreciable exposed area of the crown sheet 14, any suitable fuel, such as gas, oil or mixtures thereof being supplied to the burner under suitable pressure through a manifold 24. Manifestly other forms of burner structure and fuel, including electrical heating means, may be employed if desired.

The system of FIGS. 1 and 2 further includes a shelf member 26 projecting inwardly from the interior surface of the body section 10 of the liquid storage tank. The shelf member 26 is selected in the form of a spiral ledge and preferably extends inwardly from the wall of the tank at least a distance equal to one-tenth of the tank diameter to insure its effective performance as a collector of insoluble residues or deposits entrained in the liquid media within the tank and to prevent any substantial accumulation of the same on the liquid side of the bottom end crown sheet 14. The shelf member 26, to be effective, should be horizontal in its inward projection, or preferably slightly inclined upwardly from the horizontal. It may also extend the entire depth of the tank, although two or more complete turns of the spiral shelf 26, from a point slightly above the interior bottom surface of the crown sheet 14, have been found satisfactory in most in stallations. The inwardly projecting length of the shelf 26 may also be selected in such Width as to provide slight axially spaced overlap of adjacent convolutions of the inwardly disposed spiral marginal edge of the same.

Insoluble products or deposits entrained within the liquid media in the storage tank of FIGS. 1 and 2, including products of corrosion generated on the interior walls of the tank, are collected on the shelf 26 as a natural phenomenon of the thermal convection currents rising upwardly Within the central area of an under-fired storage tank and downwardly along the inner surface of the tank Walls. A dam 28 may be provided at the lowest point on the spiral shelf 26 to prevent the deposits accumulated and collected thereon from being discharged on the liquid contacting surface of the bottom end closure crown sheet 14. The accumulated deposits or products can also be readily flushed from the shelf 26, as required, a drainage cock 30, or other conventional clean-out opening (not shown), being provided for that purpose. Also, conventional cold inlet and hot outlet water or other liquid media conduits or pipes 32 and 34, respectively, are provided in the elevated temperature closed liquid heating and storage system of FIGS. 1 and 2. The cold water or liquid media inlet conduit or pipe 32 preferably extends axially below the hot water or liquid media outlet conduit or pipe 34, with the discharge end 33 of the conduit 32 preferably terminating above the uppermost level of the inwardly projecting area of the shelf 26 nearest thereto.

Referring now to the elevated temperature closed liquid heating and storage system of FIGS. 3 and 4, the storage tank and system illustrated therein is substantially identical to that of FIGS. 1 and 2 with the exception that the storage tank includes a conventional center flue 36 vented to atmosphere. Otherwise, the system comprises a tank having a cylindrical or body section 10, top and bottom crown sheets or plates 12 and 14, respectively, under-fired burner 22 and fuel supply manifold 24, and liquid media cold and hot conduits or pipes 32 and 34, respectively.

In this particular embodiment of the invention, the liquid storage tank is provided with two or more substantially semi-circular shelves 40, either horizontally disposed but preferably inclined slightly above the horizontal, with overlapped unsupported edges, which edges are cut-away or otherwise formed at 38 to provide an oversize central clearance passage for the central flue 36 therethrough. The lowermost shelf 49 is preferably positioned slightly above the liquid contacting interior surface of the bottom end closure crown sheet 14, and, as in the case of the system of FIGS. 1 and 2, the shelves 4!) serve to collect insoluble residues, deposits or products suspended in the liquid media of the system of FIGS. 3 and 4 and thereby prevent any substantial accumulation of the same in contact with the liquid side of the bottom end closure crown sheet 14. The cold liquid media conduit or pipe 32, in this embodiment of the invention, also preferably extends axially below the hot liquid media conduit 34, with the discharge end 33 of conduit 32 preferably terminating above the inwardly projecting area of the uppermost shelf 40. Periodic flushing of the system to remove excessive accumulations of insoluble deposits from the shelves 40 is preferably obtained by using the drainage cock 42.

The provisions of the inwardly projecting shelves 26 and 40 minimize, and in some instances substantially eliminate, the accumulation of insoluble deposits in contact with the liquid side of the bottom end closure crown sheets 14, which accumulations, as previously stated, have been found to be responsible for the rumbling noises in the operation of systems of the type hereinabove described.

Since the insoluble deposits or products with which the present invention is concerned include products of corrosion of the storage tanks proper, the location and disposition of the shelves 26 and 40 in surface contact with the interior surface of their respective liquid storage tanks insures maximum accumulation of the corrosion products developed on the interior walls of the tanks. If desired, the shelves 26 and 46 may be selected in a material anodic to the material of the storage tanks themselves and be of sufficient predetermined cross-section to provide galvanic protection for the storage tanks over the expected life of the same.

The shelves 226 and 49 are preferably imperforate and made from materials compatible with the tank bodies, as well as being capable of withstanding the temperatures of operation of the systems contemplated and disclosed hereinabove.

Having selected two specific embodiments of the invention for purposes of illustrating the same, it is to be understood that the invention is not to be limited in any way, except as defined in the following appended claims.

What is claimed is:

1. In an elevated temperature closed liquid heating and storage system having a storage tank with a bottom end under-fired closure crown sheet interiorly in contact with liquid media containing entrained insoluble products, and characterized by developing rumbling noises in the intended use of the system through accumulation of the insoluble products on the liquid contacting side of the.

under-fired bottom end crown sheet, the improvement comprising, means within the storage tank for collecting entrained insoluble products above the liquid contacting surface of the bottom end crown sheet, said collecting means comprising a shelf member in the form of a spiral convolution projecting inwardly from contact with the interior wall of the storage tank, said spiral convolution having a portion closest to the liquid contacting surface of the bottom end crown sheet spaced thereabove at a level within the storage tank below an outlet supplying the liquid media to the storage tank.

2. The system of claim 1 in which at least two complete spiral convolutions of the shelf member are employed above the liquid contacting surface of the bottom end crown sheet.

3. The system of claim 1 in which an upwardly extending dam is provided on the lowest terminal end of the shelf member.

4. In an elevated temperature closed liquid heating and storage system having a storage tank with a bottom end under-fired closure crown sheet interiorly in contact with liquid media containing entrained insoluble products, and characterized by developing rumbling noises in the intended use of the system through accumulation of the insoluble products on the liquid contacting side of the under-fired bottom end crown sheet, the improvement comprising, means within the storage tank for collecting entrained insoluble products above the liquid contacting surface of the bottom end crown sheet, said collecting means comprising a spirally convoluted shelf member extending inwardly from the interior wall of the storage tank from a point spaced slightly above the liquid contacting surface of the bottom end crown sheet and terminating at an elevation within the axial depth of the storage tank below an outlet supplying the liquid media to the same, and said shelf member providing a continuous marginal edge remote from the interior wall surface of the storage tank in spiral spaced overlapping adjacent convolutions of the same.

References Cited in the file of this patent UNITED STATES PATENTS 523,071 Humphrey et al. July 17, 1894 983,561 McPherson et al. Feb. 7, 1911 1,185,576 Baker May 30, 1916 2,814,278 Cameron Nov. 26, 1957 

